Starting a notebook hangs on "setting up proxy to JupyterLab"

Question

I have a VM instance that I'm trying to access from Notebook AI. It's been functional for about 2 months, but when I tried to start it today it gets hung up on "Setting up proxy to JupyterLab." It's been stuck on that for about 30min and I also can't SSH in to see what's going on. Any thoughts?

Edit: this is what I see in serial port log 1

Welcome to [1mDebian GNU/Linux 9 (stretch)[0m!

[    3.754088] systemd[1]: No hostname configured.
[    3.755514] systemd[1]: Set hostname to <localhost>.
[    3.958833] systemd[1]: Listening on Journal Socket (/dev/log).
[[0;32m  OK  [0m] Listening on Journal Socket (/dev/log).
[    3.974149] systemd[1]: Listening on fsck to fsckd communication Socket.
[[0;32m  OK  [0m] Listening on fsck to fsckd communication Socket.
[    3.986195] systemd[1]: Listening on udev Kernel Socket.
[[0;32m  OK  [0m] Listening on udev Kernel Socket.
[    3.988524] systemd[1]: Listening on udev Control Socket.
[[0;32m  OK  [0m] Listening on udev Control Socket.
[    4.002213] systemd[1]: Started Forward Password Requests to Wall Directory Watch.
[[0;32m  OK  [0m] Started Forward Password Requests to Wall Directory Watch.
[[0;32m  OK  [0m] Set up automount Arbitrary Executab…rmats File System Automount Point.
[[0;32m  OK  [0m] Listening on Syslog Socket.
[[0;32m  OK  [0m] Reached target Swap.
[[0;32m  OK  [0m] Reached target Remote File Systems.
[[0;32m  OK  [0m] Listening on /dev/initctl Compatibility Named Pipe.
[[0;32m  OK  [0m] Listening on Journal Socket.
[[0;32m  OK  [0m] Listening on Journal Audit Socket.
[[0;32m  OK  [0m] Started Dispatch Password Requests to Console Directory Watch.
[[0;32m  OK  [0m] Reached target Encrypted Volumes.
[[0;32m  OK  [0m] Created slice User and Session Slice.
[[0;32m  OK  [0m] Created slice System Slice.
         Mounting POSIX Message Queue File System...
         Starting Create list of required st…ce nodes for the current kernel...
         Mounting Huge Pages File System...
         Mounting Debug File System...
[[0;32m  OK  [0m] Reached target Slices.
[[0;32m  OK  [0m] Created slice system-getty.slice.
         Starting Journal Service...
[[0;32m  OK  [0m] Created slice system-serial\x2dgetty.slice.
[[0;32m  OK  [0m] Created slice system-systemd\x2dfsck.slice.
         Starting Load Kernel Modules...
[    4.224846] gve: loading out-of-tree module taints kernel.
         Starting Remount Root and Kernel File Systems...
[    4.237141] EXT4-fs (sda1): re-mounted. Opts: (null)
[[0;32m  OK  [0m] Mounted Huge Pages File System.
[[0;32m  OK  [0m] Mounted POSIX Message Queue File System.
[[0;32m  OK  [0m] Mounted Debug File System.
[[0;32m  OK  [0m] Started Journal Service.
[[0;32m  OK  [0m] Started Create list of required sta…vice nodes for the current kernel.
[[0;32m  OK  [0m] Started Load Kernel Modules.
[[0;32m  OK  [0m] Started Remount Root and Kernel File Systems.
         Starting Load/Save Random Seed...
         Starting udev Coldplug all Devices...
         Starting Apply Kernel Variables...
         Starting Create Static Device Nodes in /dev...
         Starting Flush Journal to Persistent Storage...
[[0;32m  OK  [0m] Started Load/Save Random Seed.
[[0;32m  OK  [0m] Started Apply Kernel Variables.
[    4.408785] systemd-journald[485]: Received request to flush runtime journal from PID 1
[[0;32m  OK  [0m] Started Flush Journal to Persistent Storage.
[[0;32m  OK  [0m] Started udev Coldplug all Devices.
[[0;32m  OK  [0m] Started Create Static Device Nodes in /dev.
[[0;32m  OK  [0m] Reached target Local File Systems (Pre).
         Starting udev Kernel Device Manager...
[[0;32m  OK  [0m] Started udev Kernel Device Manager.
[    4.656986] input: Power Button as /devices/LNXSYSTM:00/LNXPWRBN:00/input/input3
[    4.658353] ACPI: Power Button [PWRF]
[    4.659040] input: Sleep Button as /devices/LNXSYSTM:00/LNXSLPBN:00/input/input4
[    4.660982] ACPI: Sleep Button [SLPF]
[[0;32m  OK  [0m] Found device /dev/ttyS0.
[    4.677261] sd 0:0:1:0: Attached scsi generic sg0 type 0
[    4.678504] sd 0:0:2:0: Attached scsi generic sg1 type 0
[    4.697847] RAPL PMU: API unit is 2^-32 Joules, 3 fixed counters, 10737418240 ms ovfl timer
[    4.699520] RAPL PMU: hw unit of domain pp0-core 2^-0 Joules
[    4.703833] RAPL PMU: hw unit of domain package 2^-0 Joules
[    4.705136] RAPL PMU: hw unit of domain dram 2^-16 Joules
[    4.723655] random: crng init done
[    4.724722] random: 7 urandom warning(s) missed due to ratelimiting
[[0;32m  OK  [0m] Found device PersistentDisk.
         Starting File System Check on /dev/…58d-07f1-406b-93de-fdcf9c254ceb...
[[0;32m  OK  [0m] Started File System Check Daemon to report status.
[    4.929677] EDAC MC: Ver: 3.0.0
[    4.933734] EDAC sbridge:  Ver: 1.1.1 
[[0;32m  OK  [0m] Started File System Check on /dev/d…3b58d-07f1-406b-93de-fdcf9c254ceb.
         Mounting /mnt/disks/datadisk...
[    5.010494] EXT4-fs (sdb): Unrecognized mount option "NOFAIL_OPTION" or missing value
[[0;1;31mFAILED[0m] Failed to mount /mnt/disks/datadisk.
See 'systemctl status mnt-disks-datadisk.mount' for details.
[[0;1;33mDEPEND[0m] Dependency failed for Local File Systems.
         Starting Raise network interfaces...
[[0;32m  OK  [0m] Reached target Timers.
[[0;32m  OK  [0m] Closed Syslog Socket.
[[0;32m  OK  [0m] Reached target Login Prompts.
[[0;32m  OK  [0m] Reached target Sockets.
[[0;32m  OK  [0m] Started Emergency Shell.
[[0;32m  OK  [0m] Reached target Emergency Mode.
         Starting Create Volatile Files and Directories...
[[0;32m  OK  [0m] Reached target Paths.
[[0;32m  OK  [0m] Started Create Volatile Files and Directories.
[[0;32m  OK  [0m] Reached target System Time Synchronized.
         Starting Update UTMP about System Boot/Shutdown...
[[0;32m  OK  [0m] Started Update UTMP about System Boot/Shutdown.
         Starting Update UTMP about System Runlevel Changes...
[[0;32m  OK  [0m] Started Update UTMP about System Runlevel Changes.
[[0;32m  OK  [0m] Started Raise network interfaces.
[[0;32m  OK  [0m] Reached target Network.
[[0;32m  OK  [0m] Reached target Network is Online.
You are in emerg
Cannot open access to console, the root account is locked.
See sulogin(8) man page for more details.

Answer 1

The issue was because of a mounted disk which I had deleted and, upon doing so, learned that I setup the fstab wrong for that disk. This made the OS unbootable.

Solution was to delete the instance (but not the boot disk), create a temporary instance with the boot disk attached, fix the fstab, delete temporary instance, then create a new instance again but with the now-fixed disk as the boot disk.